Patent · US Expired

Piezoelectric servomechanism apparatus

US4765140A · kind A · utility

19Cited by
5References
13Claims
0Family size

Assignees

Inventors

Key dates

Filing dateJan 3, 1986
Grant dateAug 23, 1988
Priority date
Expiry dateJan 3, 2006

Classification

  • Technology area (CPC F)Mechanical Engineering; Lighting; Heating
  • CPC primaryF16D29/00
  • WIPO fieldTransport
  • WIPO sectorMechanical engineering

Abstract

A floating plate is provided in a cylinder chamber and slides freely like a piston. A first group of laminated, ring-shaped, thin-plate piezoelectric elements is provided between a fixed support member provided on part of a wall portion of this cylinder chamber and the floating plate. A second group of laminated, cylindrical, thin-plate piezoelectric elements is provided in the center of the first group and a working member is provided on the free end of the second group of elements that is not attached to the floating plate. A hydraulic chamber is formed in the cylinder chamber on the side of the floating plate opposite to the side on which the first and second groups of elements are provided, and the pressure in this hydraulic chamber pushes the floating plate in the direction of the fixed support member. Voltage is applied to the first and second groups of elements to expand and contract them thereby varying the distance between the floating plate and the fixed support member and varying the distance between the floating plate and the working member.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.